This invention relates to a biocidal composition. In another aspect, the invention relates to a method for disinfecting articles by contacting the article with a composition that forms on mixing various chlorine containing compounds with water.
It has long been known that various chlorine containing compounds can be used as biocidal agents. Indeed, the literature contains many references to the use of chlorine gas, various chlorites and even chlorine dioxide as materials that can be used to kill microorganisms.
Chlorine dioxide has been suggested as a strong oxidizing agent that is especially useful to kill various microorganisms.
The prior art describes many processes for the direct use of chlorine dioxide for use as a biocide. The prior art also described many processes for the production of stabilized chlorine dioxide by the addition of a variety of inorganic compounds such as inorganic boron and/or various peroxides, including hydrogen peroxide.
In spite of the large number of prior art references to chlorine dioxide, it has many short comings because it is a potentially hazardous material and is generally difficult to produce and apply where needed. Chlorine dioxide is also corrosive and its formation requires considerable amounts of acid which add to its corrosive properties.
Chlorine dioxide has been used in the treatment of water supplies and in swimming pools. In may cases, chlorine dioxide has been shown to be superior to chlorine as a bactericide. On the other hand, chlorine dioxide is dangerous to handle, cannot be stored and is explosive in the concentrated gaseous state.
In a summary entitled "THE CHEMISTRY OF CHLORINE DIOXIDE", Messrs. Gilbert Gordon, Robert G. Keiffer and David M. Rosenblatt "Progress in Inorganic Chemistry", Volume XV, S. L. Lippard, Editor John Wiley & Sons, New York, N. Y., 1972; pages 201-286, have shown a collection of 230 references related to chlorine dioxide. There are several United States Patents such as U.S. Pat. Nos. 3,123,521 and 4,104,190, relating to chlorine dioxide. U.S. Pat. No. 3,123,521 describes a stabilized chlorine dioxide as a commercial germicide using sodium carbonate peroxide. U.S. Pat. No. 4,104,190 describes difficulties with the prior art requiring a highly acid environment for generation of chlorine dioxide from chlorine dioxide precursors; for example in pH's of 2-3 or lower; and then describes a method of employing a chlorine emitter to effect production of chlorine dioxide at pH's in the range of 4-9. There is a wide variety of U.S. Patents relating the chlorine dioxide in a variety of uses.
Chlorine dioxide has been demonstrated to be an effective microbicide, for example, in the paper industry and in textile bleaching where it is also known to be a powerful and effective oxidizing agent. Prior art references such as U.S. Pat. Nos. 4,296,102 and 4,296,103 to Laso, U.S. Pat. No. 4,330,531 and Re. 31,779 to Alleger and U.S. Pat. No. 4,507,285 to Kuhne describe the use of chlorine dioxide and or stabilized aqueous solutions of chlorine dioxide.
The stabilized aqueous solutions of chlorine oxides contain chlorine dioxide as well as other dissolved oxides reported in the above patents of chlorine. In addition these solutions usually contain a peroxide, percarbonate or other oxygen donor. An essential ingredient of the Laso and Alleger patents is the presence of stabilized aqueous solutions of chlorine oxide utilizing oxygen donors.
Laso describes the preparation of solutions in his invention where chlorine dioxide may be added as a gas or formed in situ in the aqueous media. Laso reports that the chlorine dioxide is believed to be held in the form of a labile complex with a special boron compound resulting in a stabilized chlorine dioxide composition.
The usual method for using or incorporating chlorine dioxide gas is to dissolve or generate the gas to form a solution following which it is used as a bactericide.
Moreover, Alliger reports that the chlorine dioxide accelerates the metabolism of the bacterial cell to the detriment of the cell growth. Alliger also indicates that yet other credible authorities assert that the chlorine ion in chlorine dioxide goes through as many as eight possible oxidation states in passing through a pore wall. Furthermore, chlorine dioxide purportedly destroys and breaks down the cell until water is lost from the protoplasm and thereafter completely destroys or oxidizes the cell. In each of these cases the compositions are used in a relatively wide concentration range, but in every case they require the production of and/or presence of chlorine dioxide itself.
The solutions of this invention contain little or no chlorine dioxide or stabilzed chlorine dioxide. Instead solutions are disclosed which exhibit biocidal synergism which is developed between the chlorite ion, the chlorate ion and chloride ion when mixed in accordance with the procedures and in the ratios described herein. As will be more fully discussed hereafter, the instant disclosure provides for mixing various components so as to provide a "redox buffered" equilibrium of intermediate species that are extremely effective as biocidal agents. In other words, the instant invention is aimed at the formation of such intermediate species instead of the production of chlorine dioxide as taught by the prior art.
In view of the foregoing, it is readily apparent that it is desirable to have improved biocidal compositions that are safe and easy to prepare. It is also readily apparent that it is desirable to have improved methods of disinfecting various articles with very high kill rates of microorganisms. It is also highly desirable to have stable biocidal compositions that can be stored over long periods of time without appreciable loss of their biocidal properties.